I assume you're talking about the Custom Line type of turnouts.
As far as I know, Atlas only makes one size of wye turnout, which I think has a #4 (or 4.5?) angle frog - should be OK for your use.
As for the other turnouts, I'd go with a #6 minimum for what you're using.
Atlas also makes a #6 turnout in a line called "Super Switch." They are part no's 505 & 506 in their product line. I don't own any, but from what I've seen, they appear to be mechanically the same, but look more prototypical than the Custom Line turnouts. They're also generally a dollar or so more expensive than Custom Line. But they only make them in #6, code 83. Not sure why they don't make them in other sizes.
Cheapest place I've been able to find for Atlas turnouts is Model Railway Post Office
www.modelrailwaypo.com - they also advertise in Railroad Model Craftsman magazine.
...Oh, and for what it's worth, I'm not affiliated with Atlas, MRPO, or RMC in any way.